Sciencemadness Discussion Board - Radium Bromide/Chloride/Sulfide from Paint

Radium Bromide/Chloride/Sulfide from Paint

PacketStorm - 26-7-2006 at 06:30

Hi folks. I've been reading here for quite a while and you are some amazing people!

I'm astounded at the chemical knowledge most of you possess. Please tell me that at least some of you are in jobs that allow you to explore the land of chemistry and get paid for it!!

Anyhow, I did a search on here, as well as on the web, and couldn't find a sufficient answer so I thought I would make my first post and ask a radioactive/chemical separation question.

Like some others here (found in my search) I have dissolved the paint off of quite a few (I lost lost count) radium paint coated hands. The activity through a 2mm glass vial is around 11+ kCPM B+G (including daughters of course) using a small GM tube counter (RadAlert 50). Total activity has got to be at least three times that amount. In all my searching I've concluded that the radium is in the form of radium sulfide - although there are mentions of it being in the bromide form and POSSIBLY the chloride form, so my solution to my proposed separation must account for those possibilities. It is obviously also mixed with the luminous compound zinc sulfide plus various binders/glue.

The bottom line is this - has anyone managed to successfully get rid of all the zinc sulfide + actviators (cu, ag, etc.) and end up with only the radium salt by itself? I realize the amount is going to be quite small, and the extraction process must be very efficient in order to get a worthwhile yield.

I found and read the "Radiochemistry of Radium" PDF, but it doesn't get into the zinc sulfide portion of things. It's mostly related to extracting radium and uranium from ore - not separating radium salts from zinc salts.

Anyone have any ideas of getting the extremely insoluble RaS04 away from the other stuff and using fractional crystallization or whatever to concentrate it?

I did read that RaSO4 is soluble in conc H2SO4, but then that will most likely take along the zinc as well - right? I don't have a stockpile of reagents to play with - I stick mostly to the HV, radioactive, etc. side of things. Getting the proper materials shouldn't be a problem, I'm just not sure which ones to use.

On the other hand - is it anyone's opinion that the amounts of radium salt to be extracted as to be so small that this entire project is not worth undertaking?

It pains me to measure all that atomic activity inside that little vial, and yet it won't even glow in spite of being mixed with 60+ year alpha particle damaged, unglowing zinc sulfide and glue!!

Thanks in advance!!!

not_important - 26-7-2006 at 09:20

First consider how much radium you having, using the activiy count and ignoring the issue of decay daughters.

Then estimate the size of some salt of that much radium, I think the densities of the chloride, bromide, and sulfate range over 4.5 to 5.5. That will give you a very rough feel for the physical size.

Read up on how the Curies did this. Co-precipitation with barium is the normal trick for small amount; I'd not be surprised if there was barium in your samples.

A separation sequence might be
o fusion with Na2CO3 and a nitrate, in a small platinum, silver, or nickel crucible
o Dissolve the fusion results in medium strength HCl or HNO3
o Adjust the pH, hit it with H2S to drop out Zn, Ni, and other such transition elements.
o Add a barium salt, and ppt the Ba+Ra as the sulfates.

IrC - 26-7-2006 at 09:23

"extremely insoluble RaS04"

Dissolve all the not extremely insoluble components to leave the RaSO4 and filter it out. This is the approach I am using. I have also been exploring the electrochemistry of radium to see if I can get the metal as a coating on an electrode. I find it amazing that in the 21st century there still is little or no information around on this really cool element. I of course am using solvents to get rid of the glue while leaving the Zn and Ra compounds by themselves. Next is dissolve the much more soluble Zn compounds and filter. You glow is gone as the crystal structure in the zinc salt which was responsible for the glow has been destroyed.

not_important - 26-7-2006 at 09:49

You have this?

http://library.lanl.gov/cgi-bin/getfile?rc000041.pdf

RaSO4 : 0.21 mg/100 cc water ar 20 C, soluble in concentrated H2SO4 (solubility goes up with acid strength) It also tends, like BaSO4 and AgCl, to form colloids.

The glues in old dials stands a good chance of being animal based - proteins like casein or collagen. Not likely to dissolve in common organics, if old enough may be crosslinked so it doesn't dissolve in water. Simplier to just oxidise it all away, get everything into solution except stuff like SiO2 that may have been added.
.

IrC - 26-7-2006 at 10:17

http://onlinebooks.library.upenn.edu/webbin/book/browse?type...

Some useful radiochem links.

PacketStorm - 26-7-2006 at 13:22

Thanks for the replies guys...I'll check out a few more of those links.

Quote:

Originally posted by IrC: You glow is gone as the crystal structure in the zinc salt which was responsible for the glow has been destroyed.

Exactly! That's why I mentioned that in my original post!

Quote:

Originally posted by PacketStorm:
It pains me to measure all that atomic activity inside that little vial, and yet it won't even glow in spite of being mixed with 60+ year alpha particle damaged, unglowing zinc sulfide and glue!!

not_important: Yep, that's the one I have - but it seemed geared toward separation from ore - not from paint. That's where I learned that the likely Ra salt present, RaSO4, is deemed "very insoluble." It was hard for me to translate all the chemistry from ore separation over to paint separation because the problems with ore separation are mostly due to the barium impurites which behave like radium. I couldn't find any references to the Ra salt being "contaminated" with any zinc salts.

PacketStorm - 26-7-2006 at 13:36

Quote:

Originally posted by IrC
Dissolve all the not extremely insoluble components to leave the RaSO4 and filter it out. This is the approach I am using. I have also been exploring the electrochemistry of radium to see if I can get the metal as a coating on an electrode. I find it amazing that in the 21st century there still is little or no information around on this really cool element. I of course am using solvents to get rid of the glue while leaving the Zn and Ra compounds by themselves.

I'm glad someone else out there is interested in this material as well. Actually, I found this forum because my web searches actually led me to one of YOUR posts about dissolving the paint! Thanks!

Anyhow, I remember reading a post by Richard Hull where he stated that there has not been, nor will there likely ever be, any more radium isolated. I think the total production of Ra by the entire world was something on the order of 1,000g. His reasoning behind it was the horrific amount of nasties produced as waste when attempting to isolate it from pitchblende. No way in hell would the EPA or anyone else allow that kind of activity to go on in these days! If I recall correctly, he also said that only 2-3% of it was accounted for - medical use. The rest was, as he put it, "sent out on the four winds" and is now in the public domain bound up in paint on all those radium watch hands and WWII military gauges floating around.

Kinda sad actually, for like you say, not a whole lot more is known about it beyond what the Curies documented.

[Edited on 26-7-2006 by PacketStorm]

Marvin - 28-7-2006 at 06:21

I feel the need to point out a few things.

Any radium you absorb is with you for life.

By your numbers you have less than a microgram of radium, your smoke detector has more activity. Most traditional wet methods will fail for such a small amount and the chemistry will be dominated by coprecipitation behaviour.

Since the output is alpha/gamma, assuming a successful seperation you will probably not see much activity on a geiger until daughters have built up again.

I gave up on this path when I realised how much of my own chemistry ended up on the bench, the floor, down the sink even when I was being very careful.

PacketStorm - 28-7-2006 at 07:59

I appreciate the concern Marvin. You're right, working with Ra, or any radionuclide for that matter, is serious business.

I don't fool around for even a moment when dealing with these types of materials - nothing but PPE, crossflow ventilation, charcoal filters, etc. :cool:

Not only do I not want to contaminate me or my home - I don't want the hazmat team disassembling parts of my house and putting them in 55 gallon drums for burial.

You're right on about the amount of Ra salt present - it's very little. That's why I posted here to see if anyone had been successful in getting it separated from the ZnS(Ag) with good efficiency. It's probably just not worth it.

I just hate looking at all that crap in my "concentrated" vial of paint. Kind of a bummer to have it mixed with all that adhesive and alpha damaged scintillator.

However, IrC and those others that have been contemplating this project. I found an interesting document (see attached).

It looks like sodium carbonate may be the key. If you ignore the first few reactions, sodium carbonate seems to turn the RaSO4 to radium carbonate which is water soluble.

I think the serious damper on anyone trying any experimentation and finding a solution is the fear of losing their "precious" amount of Ra! It took quite a while for me to amass the amount I've got. I don't want to go through that again (or spend the money)!

[Edited on 28-7-2006 by PacketStorm]

Attachment: DeterminingRadiumContent_of_U238_MineTailings.pdf (144kB)
This file has been downloaded 1131 times

not_important - 28-7-2006 at 14:08

The sulfate to carbonate conversion works for all of the alkaline earth elements; generally the carbonate is less soluble that the sulfate, plus the conditions use an excess of Na2CO3 to help force the reaction.

However it is not a good way to get the stuff into solution to start with, plus as the sulfate ages it tends to get less reactive. The mine tailings reference starts with everything in solution, and takes advantage of the lead content to supplier a carrier for the ppt. Starting out with mixed solids can result in a potion of what you're after being trapped by the insoluble materials. That's why I suggested the Na2Co3 + nitrate fusion; it will destroy the organics, convert sulfides to carbonates or oxides, and break up and inclusions.

The tailings procedure is designed to eliminate everything else from solution. This works well when what you want to isolate is has few compounds of low solublity or is present only in small amounts.

Note that the solubility of RaSO4 is such that only a few cc of water should dissolve the amount of RaSO4 that you have.

Radium is more reactive than barium, elecrochemistry of barium will give you guidelines. You won't be plating either metal out as the pure metal, although you can deposit the metal into mercury to form an amalgam.

Marvin - 29-7-2006 at 08:32

"radium carbonate which is water soluble"

Its statements like this that speak to me the most.

I may have forgotten to mention what you are doing is illegal, but you probably knew that.

Ive never heard of using a sodium carbonate melt before, but the 'classical' step for larger amounts is to precipitate radium as the sulphate, following the sulphide step in which you lose polonium and interfering elements (such as transition metals like Zinc), filter and reflux the residue with sequential portions of sodium carbonate solution. This slowly converts the relativly soluable radium sulphate into the much less soluable radium carbonate. Treatment with dilute HCl or HBr then provides a solution that can be fractionally crystalised with later stages being done from HCl/HBr instead of water using the common ion effect to render the radium salt less soluable. This is how most of the crap is seperated.

This process pretty much can't work for amounts as small as you have. As not_important has rightly said that amount of pure radium sulphate would dissolve in about 1cc of water. Which phase your radium is in will depend on the coprecipitation chemistry. The mine tailings pdf is a good one if you can get the specific ion exchange resin they are using, otherwise you may just be diluting the radium with an element thats more difficult to seperate than what it is with allready.

As Ive mentioned before, your geiger counter will initially be of no help in locating the radium.

I'm suspect of an anodic stripping mercury drop method for such a small amount of high potential material in a large amount of low potential contaminant, but I don't have enough experience to say why. Its a clever suggestion and it certainly can work extremely well for trace elements.

not_important - 29-7-2006 at 09:13

Carbonate fusion is fairly common for breaking up samples, as is peroxide, pyrosulphate is another.

http://www.springerlink.com/(3hnp2u45tbs2pt55qsgdc045)/app/home/contribution.asp?referrer=parent&backto=issue,5,52;journal,944,2048;linkingpublica tionresults,1:110258,1

Na/K carbonate mixes are often used, to get a lower melting point. Extract the cooled melt with cold water, most metals would remain as carbonates which then could be dissolved in HCl or HNO3.

PacketStorm - 29-7-2006 at 09:45

Marvin:

"radium carbonate which is water soluble"

Yeah, I caught that one after I posted. I was thinking of radium chloride. Ooops.
RaCl2 Solubility (water) = 22 g/100 ml

Why do you say that a geiger counter would not register the radium? My counter is sensitive to alphas, which is the first particle given off by the radium decay series. Maybe you're thinking I have a typical GM tube type counter without a mica window.

Otherwise you're right, a beta/gamma sensitive detector would only begin to give readings after some of the decay daughters built up - assuming they got separated in all the prior chemistry.

[Edited on 29-7-2006 by PacketStorm]

Marvin - 29-7-2006 at 13:37

not_important,

Ive certainly read this in other areas of chemistry, I think its even a step in the yellowcake process, but not done on group 2 sulphates much less radium. My gut reaction to the idea is that under those conditions polonium might vapourise, which may not be a great thing in a lab setting.

PacketStorm,

I didn't say the Radium wouldn't be detected, I said it would be no help in locating it. Alphas are very easily stopped and a wet bulk precipitate may only see a tiny fraction of the activity of a plated disc. Gammas will be next to no help. Lets say for argument you roast the stuff in air, precipitate zinc sulphide with (TOXIC!) H2S, add a lead salt and coprecipitate the sulphate. You'll have no idea where the radium is for certain with a geiger counter. You'll see a strong signal of betas from the daughters and pretty much nothing else, if you get any alphas at all registering it could be any of half a dozen emitters. Some of the beta emitting daughters have a 20 year half life.

My point is, if you have no way of gaugeing the success how can it be worth doing?